The invention refers to a chain conveyor with chain band, particularly a double middle chain band utilized in transportation of mass goods in underground mining and tunnel construction, which is assembled from horizontal and vertical track links that are interlocking, and which is provided with pushers guided in the conveyor trough and is fitted in its partition to the chain wheels that are arranged on the ends of the conveyor trough rope, whereby the chain links have enlarged bearing surfaces which make possible a good introduction of force from the chain wheels into the chain band.
These types of chain bands with interlocking chain links are used in underground mining and tunnel construction, particularly for transportation of mined coal and rocks. Equivalent chain bands, however, are also used above ground. There, the chain bands are pulled by pressure type conveyor troughs, which are, therefore, exposed to especially high attrition. During the past years, in the development of conveyor chains, larger and larger dimensions were selected exclusively, in order to satisfy ever growing performance requirements. This development, however, has been unsatisfactory since it still does not diminish attrition, but, especially, since only an adverse introduction of force of the chain wheels into the chain bands is possible when using the round link tracks that have been in use to date. In addition, the shape of the conveyor troughs poses a dimensional limit for the chain bands.
The introduction of force in the known chain conveyors takes place via the chain wheels, which are arranged on the end sides of the conveyor trough and are connected with the driving gears or with a driving gear. In the chain bands being used today, the chain drum or chain wheel and the round link chain come into contact only punctually, which results in very high surface pressure in these punctual areas of contact. Chain bands that have been in use for a longer while, therefore, have visible notches in the areas of contact, i.e., in the area of rolling off, and show a so-called duck-tail attrition, which is caused by high surface pressure. This adverse and unsatisfactory introduction of force is the essential weak point of the round link tracks used almost exclusively today, and limits their life span considerably.
A form of track link known by DE-PS 694 515 shall achieve an improved introduction of power, whereby the chain links on both ends are built at a right angle. So far, however, this has been disadvantageous in that the attrition on the chain links, even on the end designed in a right angle, occurs so soon that only an insignificantly extended service life can be achieved for the cross-section still used. In addition, the corresponding edged chain links are a danger to the vessels of the conveyor troughs and, finally, for the area of the chain wheel. Besides, their production requires a considerable effort. Similar chain links are also known from the DE-AS 22 47 300, where the individual tail areas are designed in edged form, to enable better transmission of force. Here, also, the corresponding edged formations do not offer an advantageous form for the whole conveyor, especially since this design is exposed to extreme attrition.
In more recent times, so-called harness chain bands have been used, which are designed to avoid the punctual attack of force to the chain links that had been disadvantageous so far. In return, the requirement for a large amount of material is accepted and, as an additional essential disadvantage, completely altered chain wheels that are required due to the large partition distance of 770 mm. Therefore, traditionally, only three-tooth cylindrical lantern gears or chain wheels are used, whereby, due to the large pocket slack necessary, irregular operation, shocks and impact effects with high spikes are the result.
For the purpose of making possible an improved introduction of force and, particularly, improvement of use in rolling curve operation, another chain band is provided with a chain band where the vertical chain links are equipped with welded-on driving tappets that extend on each side in a cross angle and right angle to the direction of pull. If necessary, wearing caps may be put on top of these driving tappets, which are fitted to the form of conduct of the conveyor trough, which results in well shaped pushers. Except for the somewhat expensive connection of the wear caps with the actual pushers, i.e., the driving tappets, it is disadvantageous that special constructions are necessary which improve the introduction of force, which may be used as double chain band with appropriate effort, but will then merely achieve an insufficient transportation effect, because the pushers lie only punctually on the tread of wheels of the conveyor troughs.